Depending on the lens' focal length, the image will deform and affect how the image looks in photos.

根据镜头焦距的不同，图像会随之变形并且会影响最终的照片效果。

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Using a group of mirrors and a housing that's almost big enough to use as a coffin, Canon was able to stretch the focal-length on this SLR-specific lens to 5,150mm.

佳能的这款单反相机专用折反镜头采用了一组折反镜片，以及一个跟棺材差不多大的镜身，其焦距被拓展到5150 mm。

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What excites ophthalmologists most, and what every lens-making company wants to achieve, is an “accommodating” lens that can change its focal length in the same way that a natural lens does.

最让眼科学家兴奋的，而且每一家人工晶体制造公司都想获得的，是一种“善于适应新环境的”晶体，能像天然的晶体一样改变它的焦距。

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Exceptional resolving power and contrast at all apertures are teamed with smooth, quiet autofocusing and a rear-focus system that maintains the same lens body length during AF.

ENGADGET: Sony NEX-3N and Alpha A58 unveiled, heading to Europe this spring

The new FUJINON XF14mm (21mm) F2.8 single focal length lens offers a stunning, ultra wide angle that delivers exceptional resolution from edge to edge.

ENGADGET: Fujifilm grows X-series mirrorless lineup with 16.3-megapixel X-E1

By using this adapter to attach any K-mount lens onto a PENTAX Q series camera, the focal length of the lens is extended by approximately 5.5 times in the 35mm format.

ENGADGET: Pentax launches Q10 interchangeable lens camera, K-5 II and K-5 IIs flagship DSLRs